Quality control press release means



June 21, 1966 D. 1.. RADFORD 3,256,623

QUALITY CONTROL PRESS RELEASE MEANS Filed Dec. 28, 1964 2 Sheets-Sheet 1.5 v lr' I LINE 1H 15 5 2 22 Q 7Q 10 f I Q v //VVENTOR DAV/D L. RAD/0E0Jim .4 77'0E/VEY June 21, 1966 D. L. RADFORD 3,256,623

QUALITY CONTROL PRESS RELEASE MEANS Filed Dec. 28, 1964 2 Sheets-Sheet 2LII,

ATTORNEY United States Patent 3,256,623 QUALITY CONTROL PRESS RELEASEMEANS David L. Radfortl, Salt Lake City, Utah, assignor to McGraw-EdisonCompany, Elgin, 111., a corporation of Delaware Filed Dec. 28, 1964,Ser. No. 421,564

8 Claims. (Cl. 38-15) This invention relates to a press with means tocontrol its pressing time and operation, and has for an object to stopthe pressing operation When the fabric being pressed reaches a pre-settemperature that indicates an absence of moisture therein. Thus, theinvention is characterized by means that controls the quality of thepressing operation and also insures against fabric scorching.

Ideal pressing temperatures of different fabric vary according to theamount of moisture contained in the fabric being pressed. Thistemperature is difiicult to preset if dependent on the heat of thepressing buck, head, or both. However, if the optimum pressingtemperature of a fabric item is known, the same can be used to releasethe press when it is reached, thereby insuring uniformity of qualityregardless that the moisture content of some of the items of a runthereof is different than the content of others in said run. The presentinvention contemplates means that responds to the optimum temperature ofthe fabric and not of the pressing components to release the press andstop the pressing operation.

Either laundry or dry cleaning types of presses, presses used byclothing manufacturers, or shirt and pants pressing machines may formthe basis on which the present invention may be applied.

Another object of the invention is to provide, in means as abovecharacterized, means to cool a sensor device that responds to thetemperature of the item being pressed to re-set the control meansquickly enough for economical operation.

This invention also has for its objects to provide such Patented June21, 1966 FIG. 1a is a diagrammatic view of an amplifier-relay typecontroller shown schematically in FIG. 1.

FIG. 2 is an enlarged and fragmentary sectional view showing a sensor orthermistor, as used in the invention and applied to the head of apressing machine.

FIG. 3 is a similar view showing a sensor or thermistor as applied tothe buck of a pressing machine.

FIG. 4 is a plan view of the sensor shown in FIG. 3.

The drawings show a pressing machine 5 provided with a fixed buck 6, apress head 7, an arm 8 mounting said head on a pivot 9 on the pressframe 10, and an extensible air cylinder 11 that is so connected to saidarm 8 as means that are positive in operation, convenient in use,

easily installed in a working position and easily disconnectedtherefrom, economical of manufacture, relatively simple, and of generalsuperiority and serviceability.

The above objects are realized in a release means that comprises anamplifier-relay type of controller that responds to changes in theelectrical resistance of a thermistor that is embodied either in thehead or the buck of a pressing machine in such position as to beoperatively affected by the temperature of an item pressed, and meansoperated by said controller to automatically open the press and/or stopthe pressing operation when the optimum temperature in said item isreached. In cases where a large number of successive pressing operationsis to be performed, the spacing of the operations should rather becontrolled by the time needed to dress the buck than the time requiredfor the sensor to cool sufiiciently and re-set for the next operation.means to cause the sensor tocool with sufficient rapidity to enabledesired economically satisfactory pressing operations of a succession ofitems.

The invention also comprises novel details of construction and novelcombinations and arrangements of parts, which will more fully appear inthe course of the following description, and which is based on theaccompanying drawings. However, said drawings merely show, the followingdescription merely describes, preferred embodiments of the presentinvention, which are given by way of illustration or example only.

In the drawings, like reference characters designate similar parts inthe several views.

FIG. 1 is a schematic view showing the present quality control meansconnected to and combined with a pressing machine.

to swing the latter in a direction to lower the head 7 over the buck 6upon extension of said cylinder, and to swing the, arm 8 in a directionto raise the head upon contraction of saidcylinder. The press head 7 isshown with a heating steam chest 7a, but may be heated in other wayscommon to pressing machines.

The above, generally conventionally, inludes spring means 811 thatbiases the arm 8 to buck-raising position and a device 12 that controlsflow of compressed air to the cylinder 11 to cause the same to extendand close the press. The press includes means to release the device 12to vent, thereby relieving pressure in the cylindcr and allowing thespring means 8a to open the press. Whether such conventional means orother comparable means is used, is not material to the invention, sincethe device 12 and the cylinder 11 are so interrelated that the formercontrols the raising or lowering operations of the press head undercontrol of a temperature-actuated means.

The present invention comprises, generally, a sensor or thermistor 15mounted in the head 7 or a sensor or thermistor 16 mounted in the buck6, and control means 17 in electric circuit between the thermistor 15 or16 and the device 12 to cause the latter to control air flow to thecylinder 11.

The sensor or thermistor 15 is in the form of an elongated member thatis housed in a metal holder 20 that is welded as an upper extension ofthe head 7. The seat 21 in which the thermistor is housed is closelyspaced from the pressing surface 22 of said head so as to be sensitiveto the heat at said surface and, therefore, to the heat of an item 23that is pressed between head 7 and the Nomex buck cover 24 of theresilient or padded buck 6.

The item 23 may comprise a variety of garments or parts thereof, thesame, in this case, being wet to varying degrees as may be due to masswashing prior to pressing. The item may be single or double ply.Assuming the same to be a pants leg, it would comprise two plies or laysof wet material which, when pressed, dry under pressing heat. It will beclear that oridinarily. the item is satisfactorily pressed when fullydry and will invite scorching only if the pressing time is continuedbeyond this point.

A too short pressing time may not produce a satisfactory result. Thisinvention contemplates termination of the pressing operation at apredetermined temperature at which the item is properly pressed eventhough the pressing time may vary.

The thermistor 15 comprises a temperature-sensing device that hasnominal ohmage that covers a temperature range of to 375 F. The rangemay be wider, but may be adequately covered by a thermistor having amean or mid-point resistance of 5000 to 5600 ohms, and having a nominaldifferential of about 18.5 ohms or 1.1 F.

As shown in FIG. 1a, the thermistor 15 is incorporated in a bridgecircuit 25 in balance with a reference resistance 26 of the same ohmage,said circuit being across the low voltage power output of the secondary27 of a power transformer 28. The conductors 29 (FIG. 1) connect thethermistor to a DC. amplifier 30 of the control means 17 and the latter,in turn, is connected to relay 31 by conductors 32. A switch 33,controlled by said relay, closes a line circuit 34 to a solenoid 35 thatopens the device 12 to allow pressure to release from cylinder 11.

Except that the thermistor resistance is increased to 5600 ohms, thecontrol amplifier 17 is similar to a transistorized amplifier relaymarketed under the name Vera- Tran by Honeywell of Minneapolis,Minnesota.

It will be understood that, with the head 7 in pressing engagement withthe item 23, the thermistor resistance decreases until it reaches avalue corresponding to the optimum-temperature desired and which may beset on the calibrated knob 3511. When the garment item 23 reaches thistemperature and the resistance of the thermistor is lowest, the relay31, by way of the amplifier 30, is energized, closing the switch 33.

If the thermistor tip is close to the pressing surface, as abovedescribed, the coolness of the wet item 23 will be transmitted to saidsurface and cause a raising of the mentioned low resistance of thethermistor. Thus, the controller amplifier will re-set automatically.This would entail delaying the release circuit so the head would staydown. Thus, if the item 23 is engaged by a heat having a temperature of300 F., the head temperature will be lowered materially or to a pointabout 275 F. By setting the controller amplifier to re-set at 285 F.,there will be a range sufficient for the same to set and re-set asdesired. Then, when the item temperature next reaches 300 F., the device12 will be actuated to release the press head.

It will be seen that reliance is placed on the wet, cool item 23 tocause the thermistor to re-set, since the low temperature it causes isseveral degrees below that necessary to cause release of energy in theamplifier. Another way of lowering the temperature of the theremistor 15so that it will re-set so as to be ready for the next pressingoperation, is to cool the same as by compressed air which may come fromany suitably filtered source and advantageously comprise the air ventedfrom the device 12 when the same has been actuated to press-releasecondition. A line 36 (FIGS. 1 and 2) indicates that such a coolingmedium is conducted to the vicinity of the thermistor.

The thermistor 16 is connected in the same way as the thermistor 15 tocontrol amplifier 17. By placing the thermistor under the Nomex buckcover 24, the same is subject to the temperature transmitted by the item23 being pressed and is remote from the press head 7. This thermistorcomprises a fiat holder 37 of Teflon or other plastic material that doesnot become heat-saturated as metal would. Rulon is another such plastic.Said holder has a central opening 38 in which a thermistor head 39 islocated and spaced from the holder. Conductors 40 and 41 extend from anend of the bead 39 and are sandwiched between two fused plies of theholder, as suggested in FIG. 3. Said conductors 40 and 41 have theconductors 29 as their extensions.

The space or opening 38 traps the heat transmitted from the head 7, thesame surrounding the bead 39 for maximum effect. When the head israised, this trapped heated air is dissipated through the interstices ofthe cover 24, exposing the thermistor to hastened cooling and effectinga more rapid re-set of the amplifier after each lay of a garment.Practice has demonstrated that re-set is had within ten seconds andfrequently around five seconds.

While the foregoing has illustrated and described what is nowcontemplated to be the best mode of carrying out the invention, theconstructions are, of course, subject to modification without departingfrom the spirit and scope of the invention. It is, therefore, notdesired to restrict the invention to the particular forms ofconstruction illustrated and described, but to cover all modificationsthat may fall within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to besecured by Letters Patent is:

1. Quality control press release means comprising, in combination with apress having pressing members comprising a buck and a press head, thelatter being mounted to move between pressing engagement with the buckand under spring bias to raised position spaced from the buck:

(a) a thermistor located in one of said pressing members in closeadjacency to the pressing surfaces between the buck and head to besubjected to decrease in the electrical resistance thereof as an itembeing pressed between said surfaces increases in temperature,

(b) means to hold the head in pressing engagement with the buck againstsaid spring bias, and

(0) electrical control means energized by increase in current thereinand connected and responsive to decreased resistance of the thermistorto operate the head-holding means to head-releasing condition upon thetemperature of said item being increased to a predetermined level,thereby enabling the head to open under said spring bias.

2. Quality control press release means according to claim 1 in which thecontrol means embodies ohmageadjusting means to cause said means toenergize in a temperature range of the item being pressed of to 375 F.

3. Quality control press release means according to claim 1 in which thethermistor is embodied in the press head with an end thereof closelyspaced from the pressing surface of said head.

4. Quality control press release means according to claim 1 in which thebuck is formed as a padded body with a fabric cover, and the thermistoris incorporated in said body immediately beneath said cover.

5. Quality control press release means according to claim 1 in whichmeans is provided to cool the thermistor after the head is raised tonon-pressing position to cause rapid raising of the resistance in thethermistor.

6. Quality control press release means according to claim 1 in which thehead-holding means comprises:

(a) an extensible air cylinder connected to the head,

(b) a device to control flow of compressed air to said cylinder toextend the same and move the press head to pressing engagement with thebuck,

(c) the device having an air exhaust that opens to vent the device andthe air cylinder, the mentioned spring bias being operative to contractthe vented cylinder and cause the press head to open, and

(d) means to conduct air from said exhaust to contact, and, thereby coolthe thermistor when the head is opened.

7. In a quality control press release, the combination with the twoseparable pressing members of a pressing machine of (a) a thermistorlocated in one of the two pressing members,

(b) said thermistor being responsive to increase of temperature of anitem pressed between said members to vary its electrical resistance, and

(0) means responsive to such change in resistance of the thermistor toseparate the pressing members when the temperature level of said item isin the range of 150 to 375 F.

8. In a quality control press release, the combination with the twoseparable pressing members of a pressing machine of (a) a thermistorlocated in one of the two pressing members,

(b) said thermistor being responsive to increase of temperature of anitem pressed between said members to vary its electrical resistance,

(c) means responsive to such change in resistance of the thermistor toseparate the pressing members when the temperature level of said item isin the range of 150 to 375 F., and

(d) means to cool the thermistor after the pressing members have beenseparated to cause lowering of 1,939,043 12/1933 Davis 38-15 theresistance of the thermistor preparatory to the 2,296,910 9/1942 Davis3815 next pressing operation. 3,042,837 7/1962 Alley et a1 3822 X'References Cited y the Examiner 5 JORDAN FRANKLIN, Primary Examiner.

UNITED STATES PATENTS 1,781,482 11/1930 'SWoboda 3861 G. V. LARKIN,Assistant Examiner.

1. QUALITY CONTROL PRESS RELEASE MEANS COMPRISING, IN COMBINATION WITH APRESS HAVING PRESSING MEMBERS COMPRISING A BUCK AND A PRESS HEAD, THELATTER BEING MOUNTED TO MOVE BETWEEN PRESSING ENGAGEMENT WITH THE BUCKAND UNDER SPRING BIAS TO RAISED POSITION SPACED FROM THE BUCK: (A) ATHERMISTOR LOCATED IN ONE OF SAID PRESSING MEMBERS IN CLOSE ADJACENCY TOTHE PRESSING SURFACES BETWEEN THE BUCK AND HEAD TO BE SUBJECTED TODECREASE IN THE ELECTRICAL RESISTANCE THEREOF AS AN ITEM BEING PRESSEDBETWEEN SAID SURFACES INCREASE IN TEMPERATURE, (B) MEANS TO HOLD THEHEAD IN PRESSING ENGAGEMENT WITH THE BUCK SAID SPRING BIAS, AND